31213212 has 24 divisors (see below), whose sum is σ = 74026512. Its totient is φ = 10233600.

The previous prime is 31213211. The next prime is 31213213. The reversal of 31213212 is 21231213.

It is an interprime number because it is at equal distance from previous prime (31213211) and next prime (31213213).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 31213191 and 31213200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20589 + ... + 22052.

It is an arithmetic number, because the mean of its divisors is an integer number (3084438).

Almost surely, 2^31213212 is an apocalyptic number.

It is an amenable number.

31213212 is an abundant number, since it is smaller than the sum of its proper divisors (42813300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31213212 is a wasteful number, since it uses less digits than its factorization.

31213212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42709 (or 42707 counting only the distinct ones).

The product of its digits is 72, while the sum is 15.

The square root of 31213212 is about 5586.8785560454. The cubic root of 31213212 is about 314.8566140058.

Adding to 31213212 its reverse (21231213), we get a palindrome (52444425).

The spelling of 31213212 in words is "thirty-one million, two hundred thirteen thousand, two hundred twelve".